KR20080062186A - The method of drying semiconductor substrate - Google Patents

Abstract

A method of drying a semiconductor substrate is provided to prevent a water mark from being formed on a surface of the substrate by substituting deionized water by isopropyl alcohol. An isopropyl alcohol solution is heated by a drying temperature to generate isopropyl alcohol vapor, and then a drying atmosphere having isopropyl alcohol vapor of 0.02 to 0.1 volume% is formed. A semiconductor substrate(200) is provided under the drying atmosphere while the drying temperature is maintained. The drying temperature is 120 to 150 °C, and the semiconductor substrate is provided at a speed of 1 to 6 mm/s. Deionized water is substituted by isopropyl alcohol on the semiconductor substrate.

Description

Drying method of semiconductor substrate {THE METHOD OF DRYING SEMICONDUCTOR SUBSTRATE}

1 is a flowchart illustrating a method of drying a semiconductor substrate of the present invention.

2A and 2B are schematic views showing the drying apparatus of the semiconductor substrate of the present invention.

3 is a graph illustrating comparative examples of the present invention.

4 is a graph for explaining an embodiment of the present invention.

5A is a SEM (Scanning Electron Microscopy) photograph showing the surface of a semiconductor substrate according to an embodiment of the present invention.

5B is a scanning electron microscopy (SEM) photograph showing a surface of a semiconductor substrate according to a comparative example of the present invention.

The present invention relates to a method for drying a semiconductor substrate, and more particularly, to a method for drying a semiconductor substrate capable of preventing the formation of water spots.

The semiconductor manufacturing process may include various kinds of processes. For example, physical or chemical deposition processes and dry or wet etching processes can be said to be the main processes of semiconductor manufacturing. While each of these processes is repeated, a cleaning process is involved. The cleaning step is a step of removing impurities remaining on the semiconductor substrate during the semiconductor manufacturing step. If impurities remain on the semiconductor substrate, the characteristics of the completed semiconductor device may be degraded, or the semiconductor device may not operate so that the reliability of the semiconductor device may be reduced.

After the said washing process, a drying process is accompanied. The drying step is a step of removing the cleaning solution remaining on the semiconductor substrate after the cleaning step. For example, the cleaning solution may be deionized water. If the deionized water is not completely dried, water spots may remain on the semiconductor substrate. The water spot is a defect of the semiconductor device, and may adversely affect the electrical characteristics of the semiconductor device.

In general, a drying method using isopropyl alcohol (IPA, hereinafter referred to as "IPA") is used. First, the semiconductor substrate is provided to a cleaning tank containing deionized water. The semiconductor substrate is moved from the deionized water to a drying tank of nitrogen and IPA vapor atmosphere. In other words, the semiconductor substrate is pulled up from the deionized water and the deionized water on the semiconductor substrate is removed by the marangoni effect using surface tension. The remaining deionized water is replaced with IPA vapor to dry the semiconductor substrate.

The drying method using IPA provides IPA vapor on a semiconductor substrate. At this time, in order to improve the drying performance, it is required to provide a sufficient amount of vaporized IPA vapor. However, even when the IPA solution is sufficiently heated, a large amount of IPA vapor may drop in temperature while being provided on the semiconductor substrate. When the temperature of the IPA vapor drops, water spots may remain on the semiconductor substrate. Therefore, the characteristics of the semiconductor device may be degraded by the water spots.

Accordingly, an object of the present invention for solving the above problems is to provide a method for drying a semiconductor substrate that can improve the characteristics of the semiconductor device.

The method for drying a semiconductor substrate of the present invention for achieving the above object is to form an isopropyl alcohol vapor by heating an isopropyl alcohol (IPA) solution to a drying temperature, the amount of isopropyl alcohol vapor is 0.02 to 0.1% by volume Forming a phosphorus drying atmosphere and providing a semiconductor substrate in the drying atmosphere maintaining the drying temperature.

According to one embodiment, the drying temperature may be 120 to 150 ℃.

According to another embodiment, the semiconductor substrate may be provided in the dry atmosphere at a speed of 1 to 6 mm / s. In this case, the semiconductor substrate may be provided to the drying atmosphere from deionized water.

According to another embodiment, the step of replacing the deionized water with the IPA in the semiconductor substrate.

According to another embodiment, the dry atmosphere may further include an inert gas. In this case, the inert gas may be nitrogen.

According to another embodiment, a conductive pattern may be formed on the semiconductor substrate.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the following examples and may be embodied in other forms. Rather, the embodiments introduced herein are provided to ensure that the disclosed subject matter is thorough and complete, and that the spirit of the present invention to those skilled in the art will fully convey. In the drawings, the thicknesses of layers and regions are exaggerated for clarity. Portions denoted by like reference numerals denote like elements throughout the specification.

1, 2A and 2B, a semiconductor substrate drying method of the present invention is described. 2A and 2B are only schematic views of a drying apparatus, but are not limited thereto.

1, 2A and 2B, the semiconductor substrate is washed (S110). A conductive pattern may be formed on the semiconductor substrate. The conductive pattern may include a high dielectric metal material. The HF solution may be used to clean the semiconductor substrate.

After the semiconductor substrate 200 is cleaned, the semiconductor substrate 200 is provided to a washing tank 210 containing a rinse solution in the drying apparatus 250. The semiconductor substrate 200 is completely immersed in the rinse solution. The rinse solution removes the cleaning solution remaining on the semiconductor substrate 200. The rinse solution may be deionized water (DI water).

Nitrogen gas is provided into the drying apparatus 250 to form a nitrogen atmosphere in the drying unit 220 on the water bath 210 (S120). In addition to the nitrogen gas, an inert gas may be used. The nitrogen gas is provided to the drying unit 220 in a heated state.

The IPA vapor is formed by heating the IPA solution above the boiling point of the IPA solution (S130). If the IPA vapor temperature is less than about 120 ° C., the drying effect is low, and if it is above about 150 ° C., the drying effect is not affected. Therefore, the drying temperature of the IPA vapor is preferably about 120 to 150 ℃.

The IPA steam is provided to the drying unit 220 while maintaining the drying temperature (S140). When the amount of the IPA vapor is less than about 0.02% by volume, water spots may be generated on the surface of the semiconductor substrate, and when the amount of the IPA vapor is greater than about 0.1% by volume, the effect of removing water spots is no longer affected. Therefore, the IPA vapor is preferably provided at about 0.02 to 0.1% by volume in the drying section.

The IPA vapor is provided to the semiconductor substrate (S150). The semiconductor substrate is moved from the washing tank 210 to the drying unit 220. If the moving speed of the semiconductor substrate is less than about 1 mm / s, the process is delayed, and if it is more than about 6 mm / s, the drying efficiency may decrease. Therefore, it is preferable that it is 1-6 mm / s.

The semiconductor substrate may be pulled up from the washing tank 210 to the drying unit 220 (FIG. 2A). Alternatively, the deionized water may be discharged from the water bath to expose the semiconductor substrate to the IPA vapor (FIG. 2B). When the semiconductor substrate is provided to the drying unit, the liquid film formed on the surface of the semiconductor substrate may be thinned by applying megasonication to the washing tank.

The IPA vapor is replaced with water on the semiconductor substrate so that the semiconductor substrate is dried.

Hereinafter, examples and comparative examples of the present invention are described. Matters not mentioned by the examples and comparative examples are the same as those described above.

Example

A metal pattern was formed on the semiconductor substrate. The semiconductor substrate was cleaned using HF solution. The semiconductor substrate was immersed in a water bath containing deionized water. Heated nitrogen was charged into the drying apparatus equipped with the bath. IPA vapor was provided into the nitrogen filled drying apparatus. The IPA vapor was heated to 125 ° C. and maintained at that temperature while provided in the drying apparatus. After rinsing the semiconductor substrate, the semiconductor substrate was pulled out of the water bath into a drying apparatus comprising nitrogen and IPA vapor. At this time, the moving speed of the semiconductor substrate was 5 mm / s, the amount of the IPA vapor in the drying apparatus was about 0.04% by volume. The semiconductor substrate was left to dry for 75 seconds in the IPA vapor atmosphere. While the semiconductor substrate was drying, the temperature of the IPA vapor was maintained at 125 ° C.

Comparative Example 1

A metal pattern was formed on the semiconductor substrate. The semiconductor substrate was cleaned using HF solution. The semiconductor substrate was immersed in a water bath containing deionized water. Heated nitrogen was charged into the drying apparatus equipped with the bath. IPA steam was provided into the nitrogen-filled drying apparatus. The IPA vapor was heated to 125 ° C. After rinsing the semiconductor substrate, the semiconductor substrate was pulled out of the water bath into a drying apparatus comprising nitrogen and IPA vapor. At this time, the moving speed of the semiconductor substrate was 5 mm / s, the amount of the IPA vapor in the drying apparatus was about 0.006% by volume. The semiconductor substrate was left to dry for 75 seconds in the IPA vapor atmosphere.

Comparative Example 2

A metal pattern was formed on the semiconductor substrate. The semiconductor substrate was cleaned using HF solution. The semiconductor substrate was immersed in a water bath containing deionized water. Heated nitrogen was charged into the drying apparatus equipped with the bath. IPA vapor was provided into the nitrogen filled drying apparatus. The IPA vapor was heated to 180 ° C. After rinsing the semiconductor substrate, the semiconductor substrate was pulled out of the water bath into a drying apparatus comprising nitrogen and IPA vapor. At this time, the moving speed of the semiconductor substrate was 5 mm / s, the amount of the IPA vapor in the drying apparatus was about 0.016% by volume. The semiconductor substrate was left to dry for 75 seconds in the IPA vapor atmosphere.

Comparative Example 3

A metal pattern was formed on the semiconductor substrate. The semiconductor substrate was cleaned using HF solution. The semiconductor substrate was immersed in a water bath containing deionized water. Heated nitrogen was charged into the drying apparatus equipped with the bath. IPA steam was provided into the nitrogen-filled drying apparatus. The IPA vapor was heated to about 160 ° C. After rinsing the semiconductor substrate, the semiconductor substrate was pulled out of the water bath into a drying apparatus comprising nitrogen and IPA vapor. At this time, the moving speed of the semiconductor substrate was 5 mm / s, the amount of the IPA vapor in the drying apparatus was about 0.024% by volume. The semiconductor substrate was left to dry for 75 seconds in the IPA vapor atmosphere.

Comparative Example 4

A metal pattern was formed on the semiconductor substrate. The semiconductor substrate was cleaned using HF solution. The semiconductor substrate was immersed in a water bath containing deionized water. Heated nitrogen was charged into the drying apparatus equipped with the bath. IPA vapor was provided into the nitrogen filled drying apparatus. The IPA vapor was heated to about 175 ° C. After rinsing the semiconductor substrate, the semiconductor substrate was pulled out of the water bath into a drying apparatus comprising nitrogen and IPA vapor. At this time, the moving speed of the semiconductor substrate was 5 mm / s, the amount of the IPA vapor in the drying apparatus was about 0.032% by volume. The semiconductor substrate was left to dry for 75 seconds in the IPA vapor atmosphere.

Comparative Example 5

A metal pattern was formed on the semiconductor substrate. The semiconductor substrate was cleaned using HF solution. The semiconductor substrate was immersed in a water bath containing deionized water. Heated nitrogen was charged into the drying apparatus equipped with the bath. IPA steam was provided into the nitrogen-filled drying apparatus. The IPA vapor was heated to about 165 ° C. After rinsing the semiconductor substrate, the semiconductor substrate was pulled out of the water bath into a drying apparatus comprising nitrogen and IPA vapor. At this time, the moving speed of the semiconductor substrate was 5 mm / s, the amount of the IPA vapor in the drying apparatus was about 0.04% by volume. The semiconductor substrate was left to dry for 75 seconds in the IPA vapor atmosphere.

Comparative Example 6

A metal pattern was formed on the semiconductor substrate. The semiconductor substrate was cleaned using HF solution. The semiconductor substrate was immersed in a water bath containing deionized water. Heated nitrogen was charged into the drying apparatus equipped with the bath. IPA vapor was provided into the nitrogen filled drying apparatus. The IPA vapor was heated to about 130 ° C. After rinsing the semiconductor substrate, the semiconductor substrate was pulled out of the water bath into a drying apparatus comprising nitrogen and IPA vapor. At this time, the moving speed of the semiconductor substrate was 5 mm / s, the amount of the IPA vapor in the drying apparatus was about 0.064% by volume. The semiconductor substrate was left to dry for 75 seconds in the IPA vapor atmosphere.

3, 4, 5a and 5b, the drying characteristics of the dried semiconductor substrate by the comparative examples and embodiments will be described.

3 and 4, Comparative Examples 2 to 6 did not maintain a constant drying temperature during the drying time. Although there are differences among the comparative examples, after about 100 seconds have elapsed, the drying temperature is drastically lowered. Up to about 100 seconds the semiconductor substrate is cleaned or rinsed. Therefore, only after about 100 seconds have elapsed, the semiconductor substrate begins to dry. However, in the above comparative examples, the drying temperature of the IPA vapor dropped during the drying time. In other words, when the drying temperature drops, the IPA vapor may be liquefied and the IPA may remain in solution on the semiconductor substrate, which makes it difficult to dry the semiconductor substrate.

In the case of Comparative Example 1, the amount of IPA was small, so that the temperature did not decrease during the drying time, but the amount of IPA should be increased for effective removal of water spots.

 On the other hand, in this embodiment, the drying temperature was kept constant during the drying time. Thus, the IPA vapor is not liquefied and remains in the vapor state.

5A and 5B, no water spots remain on the semiconductor substrate dried by the embodiment. On the other hand, the water spot 500 occurred on the semiconductor substrate dried by the comparative example. As described above, in Comparative Example 1, the drying temperature was maintained, but due to the small amount of IPA vapor, the drying was not sufficient and water spots occurred on the surface of the semiconductor substrate. If the drying time is increased, the occurrence of water spots may also be reduced in Comparative Example 1, but the unit cost may be increased because the process time may be delayed.

In Comparative Examples 2 to 6, the amount of IPA is relatively high, but the water spot may remain on the semiconductor substrate because the drying temperature is not maintained.

In the embodiment, since the drying temperature is maintained and the amount of IPA is sufficient, the semiconductor substrate can be dried without remaining water spots on the semiconductor substrate within a normal processing time.

In the method for drying a semiconductor substrate of the present invention, the semiconductor substrate is dried by providing an IPA in an amount of about 0.02 to 0.1% by volume at a drying temperature maintained above the boiling point of the semiconductor substrate after the rinsing step of the semiconductor substrate. Accordingly, the present invention can dry a semiconductor substrate so that water spots do not remain on the surface of the semiconductor substrate within a normal drying process time. As a result, the reliability of the semiconductor device can be improved.

Claims (8)

Heating the isopropyl alcohol (IPA) solution to a drying temperature to form isopropyl alcohol vapor; Forming a dry atmosphere wherein the amount of isopropyl alcohol vapor is between 0.02 and 0.1 volume percent; And And providing a semiconductor substrate in the drying atmosphere maintaining the drying temperature. The method of claim 1, The drying temperature is a drying method of a semiconductor substrate, characterized in that 120 to 150 ℃. The method of claim 2, And the semiconductor substrate is provided in the drying atmosphere at a speed of 1 to 6 mm / s. The method of claim 3, wherein And said semiconductor substrate is provided in said drying atmosphere from deionized water. The method of claim 4, wherein And replacing the deionized water with the IPA in the semiconductor substrate. The method of claim 1, The drying atmosphere is a method for drying a semiconductor substrate, characterized in that it further comprises an inert gas. The method of claim 6, And the inert gas is nitrogen. The method of claim 1, And a conductive pattern is formed on said semiconductor substrate.

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